Portable refrigerator



FIG. 1 is a front elevation view of a portable refrigerator;

FIG. 2 is an opposite elevation view of the portable refrigerator;

FIG. 3 is a top plan view of the portable refrigerator;

FIG. 4 is a bottom plan view of the portable refrigerator;

FIG. 5 is a side elevation view of the portable refrigerator;

FIG. 6 is an opposite side elevation view of the portable refrigerator;

FIG. 7 is a perspective view of the portable refrigerator; and,

FIG. 8 is an environmental view of the portable refrigerator in a vehicle.

The broken lines of FIGS. 4, 5, 7, and 8 illustrate portions of the portable refrigerator or illustrate environmental matter that form no part of the claimed design. 

CLAIM The ornamental design for a portable refrigerator, as shown and described. 